move lock check into HealthChecker

to avoid dependency of HttpController on LockManager in unit tests

services/track-changes/app/coffee/HealthChecker.coffee

@@ -4,6 +4,7 @@ async = require("async")
 settings = require("settings-sharelatex")
 port = settings.internal.trackchanges.port
 logger = require "logger-sharelatex"
+LockManager = require "./LockManager"
 
 module.exports =
 	check : (callback)->
@@ -37,3 +38,6 @@ module.exports =
 						cb()
 		]
 		async.series jobs, callback
+
+	checkLock: (callback) ->
+		LockManager.healthCheck callback

services/track-changes/app/coffee/HttpController.coffee

@@ -5,7 +5,6 @@ RestoreManager = require "./RestoreManager"
 logger = require "logger-sharelatex"
 DocArchiveManager = require "./DocArchiveManager"
 HealthChecker = require "./HealthChecker"
-LockManager = require "./LockManager"
 _ = require "underscore"
 
 module.exports = HttpController =
@@ -118,7 +117,7 @@ module.exports = HttpController =
 				res.send 200
 
 	checkLock: (req, res)->
-		LockManager.healthCheck (err) ->
+		HealthChecker.checkLock (err) ->
 			if err?
 				logger.err err:err, "error performing lock check"
 				res.send 500

services/track-changes/test/unit/coffee/HttpController/HttpControllerTests.coffee

@@ -14,6 +14,7 @@ describe "HttpController", ->
 			"./RestoreManager": @RestoreManager = {}
 			"./PackManager": @PackManager = {}
 			"./DocArchiveManager": @DocArchiveManager = {}
+			"./HealthChecker": @HealthChecker = {}
 		@doc_id = "doc-id-123"
 		@project_id = "project-id-123"
 		@next = sinon.stub()